Highly dense integrated coating for marine environment and method for preparing the same

Abstract

The application discloses a kind of high-density integrated coating for marine environment and preparation method thereof, belong to coating protection technology.The preparation method of the application includes: (1) micron nickel-copper alloy powder is mixed with micron titanium oxide powder by ball milling and dried, to obtain mixed powder, Al is contained in micron nickel-copper alloy powder;(2) the mixed powder and polyether ether ketone powder are uniformly mixed and dried, to obtain spraying raw material;(3) using flame spraying, the spraying raw material is sprayed to the surface of substrate.(4) after spraying, the surface of coating is treated by flame spraying technology.The application effectively improves the comprehensive performance of coating, such as corrosion resistance and wear resistance, by optimizing the coating formula and the preparation method, so that the coating forms long-term protection for the metal substrate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of coating protection, and relates to a high-density integrated coating for marine environment and a preparation method thereof. BACKGROUND

[0002] With the expansion of the global market and the development of naval modernization, higher requirements are put forward for the research and development, manufacturing technology and production capacity control of the shipbuilding industry of China. The metal components applied in the shipbuilding industry will be corroded by seawater during long-term service, therefore, the surface of the metal components must be treated for long-term protection to inhibit the occurrence of corrosion and ensure the long-term stable operation of the complete equipment of the shipbuilding industry. At present, the coating is usually coated on the surface of the metal component to protect the metal component by the coating, therefore, the performance of the coating directly affects the protection effect of the coating on the metal component, and the better the density and corrosion resistance of the coating, the better the protection effect of the coating on the metal component in a longer period of time.

[0003] Therefore, it is necessary to provide a high-density integrated coating for marine environment and a preparation method thereof, so as to obtain a coating with excellent density and corrosion resistance, and to protect the metal component for a long time. SUMMARY

[0004] In order to overcome the problems in the background art, the application optimizes the composition of the coating combined with the preparation method, so that the coating has excellent density and corrosion resistance, thereby protecting the metal component for a long time by the coating of the application, prolonging the service life of the metal component and improving the use stability of the metal component.

[0005] In order to achieve the above-mentioned purpose, the application realizes the technical scheme as follows:

[0006] The application provides a preparation method of a high-density integrated coating for marine environment, which comprises the following steps:

[0007] (1) micron-sized nickel-copper alloy powder and micron-sized titanium oxide powder are ball-milled and mixed and dried to obtain a mixed powder, wherein the micron-sized nickel-copper alloy powder contains Al;

[0008] (2) the mixed powder obtained in step (1) and polyether ether ketone powder are uniformly mixed and dried to obtain a spraying raw material;

[0009] (3) the spraying raw material obtained in step (2) is sprayed onto the surface of a substrate by using flame spraying.

[0010] (4) after the spraying in step (3) is completed, the surface of the coating is treated by using flame spraying technology. The thickness of the coating is preferably 200-300 microns.

[0011] Preferably, in the step (1), the ball milling ball-to-material ratio is 8:1, and the ball milling rotation speed is 500 rpm.

[0012] Preferably, in the step (2), the drying temperature is 120℃, and the drying time is 4h.

[0013] Preferably, in the steps (3) and (4), the oxygen flow rate for flame spraying is 800 L / min, the oxygen pressure is 1.5 MPa, the kerosene flow rate is 25 L / h, the kerosene pressure is 0.8 MPa, the spraying distance is 350-380 mm, and the feeding speed is 3.5 g / min.

[0014] In another aspect of the present application, the coating prepared by the above preparation method is provided, and the composition of the nickel-copper alloy powder includes, in terms of mass fraction, Cu: 20%, Al: 10-12%, Cr: 5-8%, Fe: 2.5%, Mn: 2%, Y: 0.5-0.8%, and the balance of Ni.

[0015] Preferably, the composition of the coating includes, in terms of mass fraction, 20% of nickel-copper alloy powder with a particle size of 5 μm, 20% of nickel-copper alloy powder with a particle size of 15 μm, 20% of nickel-copper alloy powder with a particle size of 30 μm, 20% of titanium oxide, and 20% of polyether ether ketone with a particle size of 15 μm.

[0016] The present application has the following advantages:

[0017] 1. The present application can form an amorphous oxide film between the metal particles and the PEEK by mixing the polyether ether ketone (PEEK) into the spraying raw material and spraying the spraying raw material onto the surface of the metal substrate by flame spraying, and the C=O bond in the PEEK reacts with the Al 3+ in the amorphous oxide film to form a metal-polymer complex at the PEEK / amorphous oxide interface, and the chemical combination between the two helps to improve the compactness of the coating.

[0018] 2. The present application can significantly improve the wear resistance and strength of the coating by adding TiO2 hard ceramic particles in the spraying raw material, thereby strengthening the comprehensive performance of the coating and making the coating have better protection effect.

[0019] 3. The present application can form a dense aluminum oxide and chromium oxide layer by optimizing the formula of the nickel-copper alloy powder and performing flame spraying treatment on the surface of the coating, effectively isolating the surface of the coating from the external environment, improving the high-temperature oxidation resistance of the coating, and improving the corrosion resistance of the coating by forming a dense oxide film with the easily passivated metals aluminum and chromium, and the addition of yttrium can catalyze grain refinement and improve defects such as micropores and microcracks, which is beneficial to improving the compactness of the coating, thereby making the coating have better protection effect.

[0020] 4. The addition of yttrium can not only improve the density of the coating, but also dissolve oxygen and inhibit Cl - Migration into the corrosion product and Al 3+ The migration of metals to the outside of the corrosion products increases the impedance of the coating, thereby making the coating exhibit better corrosion resistance.

[0021] 5. The present invention can form an integrated coating on the surface of the metal substrate through a single flame spraying to provide long-term protection for the metal substrate. The coating preparation process is simple and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a metallographic image of the sample after spraying the coating of the present invention;

[0023] Figure 2 is a graph of the coefficient of friction of the coating of the present invention;

[0024] Figure 3 The impedance diagram of the sample after being sprayed with the coating according to the present invention and immersed in a 3.5% NaCl solution for 0.5 h. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to specific embodiments.

[0026] In the examples and comparative examples of the present invention, chemical reagents not otherwise specified were commercially available analytically pure for use in the experiments.

[0027] During the experiments of the embodiments of the present invention and the comparative examples, conventional nickel-copper alloy was selected as the metal substrate, and the metal substrate sample was prepared into a Φ28mm*2mm disc by using electric spark wire cutting. The sample surface was polished in sequence using 240 mesh, 400 mesh, 600 mesh, 800 mesh, and 1000 mesh sandpaper, and then the polished sample was sandblasted. After sandblasting, the sample was placed in alcohol for ultrasonic cleaning for 30 minutes.

[0028] Sandblasting involves accelerating white corundum sand particles through a high-speed stream of compressed air, causing them to impact the sample surface at high speed. This intense and sustained impact strips away grease and oxide layers from the sample's surface, completely removing them and revealing the fresh metal matrix. Simultaneously, the impact creates numerous tiny pits on the sample's surface, roughening it.

[0029] Sandblasting is carried out using a mobile sandblasting machine with the following process parameters: the compressed air pressure used is 0.6 MPa, the distance between the sandblasting gun nozzle and the sample surface is 30 to 50 mm, the sandblasting angle range is 50 to 90°, the spray gun moving speed is 2 m / min, and the surface roughness after sandblasting reaches Sa2 level or above.

[0030] Before spraying the coating, the metal substrate sample surface is preheated to 300-500℃, to remove the moisture and condensate on the surface of the workpiece, to improve the bonding strength of the coating and the substrate, and to reduce the stress caused by the temperature difference between the coating and the substrate.

[0031] In the examples and comparative examples of the present application, the nickel-copper alloy treated as described above is used as the metal substrate. The coating thickness is 200-300 μm.

[0032] Example 1

[0033] This example is prepared according to the following steps:

[0034] (1) The nickel-copper alloy powder raw material is weighed according to the mass fraction of Cu: 20%, Al: 10%, Cr: 8%, Fe: 2.5%, Mn: 2%, Y: 0.5%, and the balance of Ni, and a sand mill is used to grind the raw material to prepare nickel-copper alloy powder of different particle sizes. The grinding line speed is 10 m / s, the cooling water flow is 750 L / h, the cooling water temperature is 7-12℃, and the grinding medium size is 1 mm (L95 zirconia beads). The grinding time is controlled to regulate the powder particle size. The nickel-copper alloy powder with particle sizes of 5 μm, 15 μm and 20 μm requires grinding for 10 h, 8 h and 6 h, respectively.

[0035] (2) The nickel-copper alloy powder with a particle size of 5 μm, the nickel-copper alloy powder with a particle size of 15 μm, the nickel-copper alloy powder with a particle size of 20 μm, the titanium oxide powder, and the polyether ether ketone powder with a particle size of 15 μm are weighed with a mass fraction of 20%, respectively. First, the nickel-copper alloy powder with different particle sizes and the titanium oxide are mixed by ball milling under the conditions of a ball-to-material ratio of 8:1 and a ball milling speed of 500 rpm, and then dried at 120℃ for 4 h to obtain a mixed powder. By using a reasonable proportion of different particle sizes, the small particle size powder can effectively fill the voids in the coating during spraying, thereby forming a dense coating structure.

[0036] (3) The mixed powder obtained in step (2) and the weighed polyether ether ketone powder are uniformly mixed and dried at 120℃ for 4 h to obtain a spraying raw material. The mixing method can use a powder mixer for stirring and mixing. The motor power of the powder mixer is 0.25 KW, the stirring speed is 50 rpm, the mixing time is 30 min, the mixing tank overturning angle is 25.3°, and the mixing tank overturning speed is 45° / s. After mixing, the spraying raw material is obtained.

[0037] (4) Set the flame spraying oxygen flow rate to 800 L / min, the oxygen pressure to 1.5 MPa, the kerosene flow rate to 25 L / h, the kerosene pressure to 0.8 MPa, the spraying distance to 350 mm, and the feeding speed to 3.5 g / min, and then spray the spraying raw material to the surface of the metal substrate by the flame spraying method.

[0038] (5) After the spraying is completed, keep the flame spraying parameters unchanged, and then use the flame spraying gun to perform high-temperature treatment on the surface of the coating, so as to complete the coating preparation process.

[0039] The metal substrate on which the coating is prepared in this embodiment is subjected to a metallographic experiment, and the result is shown in FIG. 6. Figure 1 The metal substrate on which the coating is prepared in this embodiment is subjected to a wear test, and the result is shown in FIG. 7. Figure 2 The metal substrate is subjected to corrosion resistance testing by using an electrochemical workstation, and the result is shown in FIG. 8. Figure 3

[0040] As can be seen from FIG. 5, Figure 1 It can be seen that the coating of this embodiment has no obvious defects such as cracks, slag inclusions and continuous holes at the interface, and shows good compactness. The high-speed particles of the flame spraying technology impact the surface of the metal substrate to form many pit structures, and the alloy coating is combined with the substrate metal in a mechanical inlaying and micro-metallurgical combination manner; meanwhile, a layer of amorphous oxide film is formed between the metal particles in the coating and PEEK, and the C=O bond in PEEK reacts with Al 3+ in the amorphous oxide film to form a metal-polymer complex at the PEEK / amorphous oxide interface, so as to improve the microstructure of the coating, further improve the compactness of the coating, reduce pores and defects, effectively prevent the penetration of corrosive medium and reduce stress concentration, and thus improve the overall corrosion resistance and durability of the coating.

[0041] As can be seen from FIG. 7, Figure 2 The friction coefficient of the coating of this embodiment is 0.31, which is greatly reduced compared with the Ni-Cu coating, indicating that the addition of ceramic particles significantly enhances the wear resistance of the coating.

[0042] As can be seen from FIG. 8, Figure 3 The impedance value of the coating of this embodiment is 85 kΩ, which is increased by 65% compared with the Ni-Cu coating. Since the coating is uniform and dense and contains a metal-polymer complex inside, the complex can improve the electrochemical stability of the coating. In addition, the complex can promote the synergistic effect of different metals to form a more complex phase structure, thereby improving the corrosion resistance of the coating.

[0043] Example 2

[0044] ​The metal substrate with coating was prepared by the same method as in Example 1, except that in this example, the raw material of the nickel-copper alloy powder was Cu: 20%, Al: 11%, Cr: 6.5%, Fe: 2.5%, Mn: 2%, Y: 0.65%, and the balance was Ni. The flame spraying distance was 380 mm.

[0045] The performance of the coating in this example was similar to that in Example 1.

[0046] Example 3

[0047] The metal substrate with coating was prepared by the same method as in Example 1, except that in this example, the raw material of the nickel-copper alloy powder was Cu: 20%, Al: 12%, Cr: 5%, Fe: 2.5%, Mn: 2%, Y: 0.8%, and the balance was Ni. The flame spraying distance was 360 mm.

[0048] The performance of the coating in this example was similar to that in Example 1.

[0049] Comparative Example 1

[0050] The metal substrate with coating was prepared by the same method as in Example 1, except that in this example, the raw material of the nickel-copper alloy powder was Cu: 20%, Al: 12%, Cr: 5%, Fe: 2.5%, Mn: 2%, Y: 0.8%, and the balance was Ni. The flame spraying distance was 360 mm.

[0051] In this comparative example, the interface between the PEEK layer and the nickel-copper alloy-titanium oxide layer was relatively clear, while the complex was only formed at the interface between the metal particles and the PEEK in the coating. If the complex was formed, it would block the interface when observed, making the interface less clear. Therefore, the interface between the PEEK layer and the nickel-copper alloy-titanium oxide layer was relatively clear, indicating that no complex was produced or very little complex was produced in this comparative example, resulting in a significant reduction in the chemical bonding force between the coatings. The chemical bonding force between the coatings is a key factor affecting the compactness of the coating and resistance to external factors such as corrosive media and mechanical stress, and its weakening will directly affect the durability and reliability of the coating. At the same time, due to the significant performance difference between the PEEK coating and the alloy coating, mainly in terms of thermal expansion coefficient, mechanical strength and chemical stability, the stress generated thereby will accelerate the peeling process of the coating, thereby affecting the service life of the coating.

[0052] In summary, by optimizing the coating formula and combining the preparation method, the present application can effectively improve the corrosion resistance, wear resistance, compactness, high-temperature oxidation resistance and other properties of the coating, and form long-term protection for the metal substrate.

[0053] Finally, it should be noted that the above preferred embodiments are merely intended to illustrate the technical solutions of the present application, not to limit the present application. Even though the present application has been described in detail by the above preferred embodiments, those skilled in the art should understand that various modifications can be made in form and details thereof without departing from the scope of the present application as defined by the appended claims.

Claims

1. A method for preparing a high-density integrated coating for marine environment, characterized by: The preparation method comprises the following steps: (1) ball-milling micron-sized nickel-copper alloy powder and micron-sized titanium oxide powder to obtain a mixed powder, wherein the micron-sized nickel-copper alloy powder contains Al; The nickel-copper alloy powder comprises, by mass fraction, Cu: 20%, Al: 10-12%, Cr: 5-8%, Fe: 2.5%, Mn: 2%, Y: 0.5-0.8%, and the balance is Ni; (2) uniformly mixing the mixed powder obtained in step (1) and the polyetheretherketone powder and drying them to obtain a spraying raw material; (3) spraying the spraying raw material obtained in step (2) onto the surface of the substrate using flame spraying; (4) After the spraying in step (3) is completed, the coating surface is treated by flame spraying technology; The coating comprises, by mass fraction, 20% nickel-copper alloy powder with a particle size of 5 μm, 20% nickel-copper alloy powder with a particle size of 15 μm, 20% nickel-copper alloy powder with a particle size of 20 μm, 20% titanium oxide, and 20% polyetheretherketone with a particle size of 15 μm.

2. The method for preparing a high-density integrated coating for marine environment according to claim 1, characterized in that: In the step (1), the ball-to-material ratio of the ball milling is 8:1, and the ball milling speed is 500 rpm.

3. The method for preparing a high-density integrated coating for marine environment according to claim 1, characterized in that: In the step (2), the drying temperature is 120° C. and the drying time is 4 hours.

4. The method for preparing a high-density integrated coating for a marine environment according to claim 1, characterized in that: In steps (3) and (4), the oxygen flow rate of flame spraying is 800 L / min, the oxygen pressure is 1.5 MPa, the kerosene flow rate is 25 L / h, the kerosene pressure is 0.8 MPa, the spraying distance is 350-380 mm, and the feed rate is 3.5 g / min.

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